Public water system · MA3346000
ActiveWinthrop Water Division, (MWRA)
At a glance
Winthrop Water Division, (MWRA) (PWSID MA3346000) is an active community water system in Suffolk County, Massachusetts. It reports serving 19,316 people through 4,547 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. EPA's records list 10 violations for this system; 8 are health-based, and the most recent began in January 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
19,316
Service connections
4,547
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Winthrop Water Division, (MWRA) compare with other water systems in Suffolk County?
By EPA's size categories, Winthrop Water Division, (MWRA) is a large system (10,001 to 100,000 people). Suffolk County has 9 active public water systems, and Winthrop Water Division, (MWRA) is the 5th-largest of them by population served. Its population served is well below the county average of 375,415 people per system, and accounts for 0.6% of the 3,378,736 people reported by systems filed under the county. Across Massachusetts, the 1,636 active systems average 6,275 people each. Nationally, the average active community water system reports serving 6,703 people, so Winthrop Water Division, (MWRA) is about 188% above that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Massachusetts has 531 active community water systems, 32% of the state's 1,636 active systems. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 126 Massachusetts systems (7.7%) list purchased surface water as their primary source.
Who owns and regulates Winthrop Water Division, (MWRA)?
EPA lists Winthrop Water Division, (MWRA) as owned by a local government. The MA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 4 of the 9 active systems in Suffolk County (44%) are also owned by a local government.
Does Winthrop Water Division, (MWRA) have drinking water violations?
EPA's records list 10 violations for this system; 8 are health-based, and the most recent began in January 2024. The violations listed here began between July 1982 and January 2024. By type: 6 required treatment not met, 2 contaminant level above the legal limit, 1 monitoring and reporting and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Lead and Copper Rule (6 of them). EPA lists 6 as resolved, 3 as archived and 1 as addressed. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status. Addressed means the violation is not resolved or archived and is covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2024-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Addressed |
| 2015-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2011-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2007-01-01 | Required treatment not metLead Service Line Replacement (LSLR) · code 64 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2001-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1994-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1993-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1992-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1992-01-01 | Required treatment not metFailure to Filter (SWTR) · code 42 | Surface Water Treatment Rulecode 0200 | Yes | Archived |
| 1982-07-31 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
All 10 violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Winthrop Water Division, (MWRA): frequently asked questions
Who runs Winthrop Water Division, (MWRA)?
Winthrop Water Division, (MWRA) (PWSID MA3346000) is a community water system owned by a local government. It is regulated by the MA state drinking water program.
How many people does Winthrop Water Division, (MWRA) serve?
Winthrop Water Division, (MWRA) reports serving 19,316 people through 4,547 service connections in Suffolk County, Massachusetts.
Where does Winthrop Water Division, (MWRA) get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Winthrop Water Division, (MWRA) have any drinking water violations?
EPA's records list 10 violations for this system; 8 are health-based, and the most recent began in January 2024. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Winthrop Water Division, (MWRA)'s water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. EPA's records list 10 violations for this system; 8 are health-based, and the most recent began in January 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the MA state drinking water program.
Where can I find Winthrop Water Division, (MWRA)'s water quality report?
As a community water system, Winthrop Water Division, (MWRA) must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Suffolk County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| MWRA | Suffolk | 2,580,000 | Community | Surface water |
| Boston Water and Sewer Commission (MWRA) | Suffolk | 675,647 | Community | Purchased surface water |
| Revere Water Division (MWRA) | Suffolk | 62,186 | Community | Purchased surface water |
| Chelsea Water Dept. (MWRA) | Suffolk | 40,787 | Community | Purchased surface water |
| Rocky Mt Sprg @ Supreme Liq Boston Vnd | Suffolk | 400 | Transient non-community | Purchased groundwater |
| Deer Island (MWRA) | Suffolk | 350 | Non-transient non-community | Purchased surface water |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Winthrop Water Division, (MWRA), PWSID MA3346000, Massachusetts”, https://aquacensus.com/water-systems/massachusetts/winthrop-water-division-mwra-ma3346000 (data as of October 1, 2026).